Number of (w,x,y,z) with all terms in {1,...,n} and w^2<x^2+y^2+z^2.

Terms

a(0) =0a(1) =1a(2) =15a(3) =73a(4) =231a(5) =562a(6) =1155a(7) =2133a(8) =3632a(9) =5801a(10) =8830a(11) =12907a(12) =18264a(13) =25131a(14) =33766a(15) =44461a(16) =57524a(17) =73274a(18) =92043a(19) =114213a(20) =140173a(21) =170289a(22) =205057a(23) =244884a(24) =290251a(25) =341658a(26) =399594a(27) =464582a(28) =537200a(29) =618046